With the progressive development of TFT-LCD (Thin Film Transistor. Liquid Crystal Display) display technology, various novel semiconductor elements and their application technologies in display devices have made rapid progress.
In a known manufacturing process of TFT-LCDs, more and more manufacturers began to use oxide TFT instead of a-Si (amorphous silicon) TFT or LTPS (low temperature polysilicon) TFT in the hope of obtaining display products with higher quality. Unlike the traditional a-Si TFT where the semiconductor active layer is made of an oxide semiconductor material, the Oxide TFT backboard technology replaces the silicon semiconductor material with an oxide semiconductor material, such as IGZO (Indium Gallium Zinc Oxide) commonly used at present. A known oxide TFT array substrate is typically as illustrated in FIG. 1, which comprises a gate 11, a gate insulating layer 12 and a semiconductor active layer 13 formed of IGZO, the three layers are formed on a base substrate 10 in this order. An etching stop layer 14 with vias A and B is formed on a surface of the semiconductor active layer 13 with a patterning process. The vias A and B penetrate the etching stop layer 14 respectively to expose the semiconductor active layer 13. A source 151 and a drain 152 of a TFT are electrically connected with the semiconductor active layer 13 through the vias A and B, respectively.